This invention relates to lamp assemblies in general and automobile dome lights in particular.
Lamp assemblies used for area illumination in automotive interior lighting applications have traditionally been implemented as multi-component assemblies which may include a lamp, lamp housing, cover lens, reflector, lamp holder, electrical contacts, and wiring to conduct power from the connector to the lamp holder where the lamp is mounted. In an effort to reduce cost and complexity of these assemblies, certain of these components are sometimes integrated together; for example, molding the electrical connector as a unitary part of the lamp housing. While perhaps complicating the initial layout and design work for the lamp assemblies, this integration can result in lower overall program cost once the resulting manufacturing and assembly efficiencies are realized.
U.S. Pat. No. 5,947,586 to Weber discloses another such example wherein an injection molded body includes unitary clamp brackets with a metallized surface that routes operating power from blade contacts to the clamp brackets which hold a glow lamp. The metallized surface can also be utilized as a reflector for the lamp. Although this design achieves integration of a number of the above-noted components, it involves a multi-step fabrication process in which an injection-molded conductor molding is formed and then encased in part using a second injection molding step where plastic is coated over the conductor molding in all locations that are not to be metallized. The remaining uncoated surface portions of the conductor molding are then metallized. An alternative fabrication process is disclosed in which no conductor molding is used; rather, the plastic lamp housing is metallized using a semi-additive process in which an electrolytic copper is coated on the housing, a photoresist is then applied which is exposed with a spatial mask (3D mask), the exposed area is developed with the photoresist, and electrolytic copper is then applied and thinned using an etching mask, followed by removal of the photoresist and etching away of the unneeded copper. These fabrication methods can add sufficient complexity and cost to the manufacturing of the lamp assembly that they may erode away any benefit obtained by the reduced part count and simplified final assembly.
It is therefore a general object of the invention to provide a lamp assembly which integrates together various functional components of the assembly while maintaining simplified manufacturing and final assembly of the component parts together.
In accordance with one aspect of the invention, there is provided a lamp assembly that includes a lamp housing supporting an optical reflector having first and second electrically-conductive reflector portions that are electrically isolated from each other, with the first reflector portion including a first unitary electrical terminal and a first unitary lamp retainer, and the second reflector portion including a second unitary electrical terminal and a second unitary lamp retainer. The first and second unitary lamp retainers can be used to mount a lamp of the type having exposed terminals, such as a cartridge lamp, with one of the lamp terminals being electrically connected to the first unitary lamp retainer and the other of the lamp terminals being electrically connected to the second unitary lamp retainer such that operating current received by the first unitary electrical terminal can flow to the first unitary lamp retainer, then through the lamp to the second unitary lamp retainer and then to the second unitary electrical terminal. The lamp housing can be made from plastic so that the reflector portions can be mounted directly to the lamp housing without creating an electrical short between the reflector portions.
In accordance with another aspect of the invention, the optical reflector can be formed from a unitary piece of stamped metal that includes a central region formed from a pair of curved portions of the stamped metal, with the curved portions being connected by one or more frangible bridges. These frangible bridges can then be separated prior to, during, or after attachment of the curved reflector portions to the lamp housing so that the reflector portions then become electrically isolated from each other. Preferably, the lamp assembly can be manufactured by stamping the connected reflector portions from a single piece of electrically-conductive metal, then attaching the reflector to the lamp housing and separating the reflector portions at the frangible bridges. Preferably, the reflector portions are insert molded into the housing.